Capacity control valve

ABSTRACT

A capacity control valve includes a valve housing provided with a suction fluid supply chamber to which a suction fluid of suction pressure Ps is supplied, and a control fluid supply chamber to which a control fluid of control pressure Pc is supplied, a CS valve formed by a CS valve element driven in the axial direction by a solenoid, and a CS valve seat provided in a communication passage between the control fluid supply chamber and the suction fluid supply chamber, the CS valve being connectable to and separable from the CS valve seat, and a pressure drive portion arranged in the control fluid supply chamber in a sealed manner and biasing the CS valve element in the opposite direction to the driving direction by the solenoid.

TECHNICAL FIELD

The present invention relates to a capacity control valve that variablycontrols capacity of a working fluid, for example, a capacity controlvalve that controls a discharge amount of a variable displacementcompressor used for an air conditioning system of an automobile inaccordance with pressure.

BACKGROUND ART

A variable displacement compressor used for an air conditioning systemof an automobile, etc. includes a rotating shaft to be driven androtated by an engine, a swash plate coupled to the rotating shaft insuch a manner that a tilt angle is variable, compressing pistons coupledto the swash plate, etc., and by changing the tilt angle of the swashplate, changes a stroke amount of the pistons to control a dischargeamount of a fluid. This tilt angle of the swash plate can becontinuously changed by appropriately controlling pressure in a controlchamber while utilizing suction pressure Ps of a suction chamber thatsuctions the fluid, discharge pressure Pd of a discharge chamber thatdischarges the fluid pressurized by the pistons, and control pressure Pcof the control chamber that houses the swash plate, with using acapacity control valve to be driven to open and close by electromagneticforce.

At the time of continuously driving the variable displacementcompressor, the capacity control valve performs normal control in whichenergization is controlled by a control computer, a valve element ismoved in the axial direction by electromagnetic force generated in asolenoid, and a CS valve provided between a control port through which acontrol fluid of the control pressure Pc passes and a suction portthrough which a suction fluid of the suction pressure Ps passes isopened and closed to adjust the control pressure Pc of the controlchamber of the variable displacement compressor.

For example, a capacity control valve shown in Patent Citation 1 ismainly formed by a valve housing including a control fluid supplychamber to which a control fluid is supplied and a suction fluid supplychamber to which a suction fluid is supplied, and a CS valve capable ofopening and closing a communication passage between the control fluidsupply chamber and the suction fluid supply chamber. By opening andclosing the communication passage by the CS valve, control pressure Pcof the control fluid supply chamber is adjusted. In this capacitycontrol valve, a pressure sensitive body extendable and contractible inaccordance with suction pressure Ps is arranged in the suction fluidsupply chamber, and the pressure sensitive body biases a CS valveelement of the CS valve which moves in the valve closing direction inthe valve opening direction. According to this, at the time of driving asolenoid, the pressure sensitive body is contracted in a case where thesuction pressure Ps is high, and the pressure sensitive body is extendedin a case where the suction pressure Ps is low. Thus, it is possible tochange an opening degree of the CS valve in accordance with the suctionpressure Ps and finely adjust the control pressure Pc.

CITATION LIST Patent Literature

-   Patent Citation 1: JP 5983539 B2 (PAGE 8, FIG. 3)

SUMMARY OF INVENTION Technical Problem

In the air conditioning system as described above, when an operation ofchanging an output of the air conditioning system is performed, anoutput of an expansion valve is increased or decreased, and a flow rateof the suction fluid supplied to a suction chamber of a variabledisplacement compressor and suction fluid pressure are also changed.

However, in the capacity control valve of Patent Citation 1, thepressure sensitive body is extendable and contractible in accordancewith only the suction pressure Ps. Thus, when an operation of a radicaloutput change of the air conditioning system is performed, there is apossibility that it takes time to adjust the variable displacementcompressor to target control pressure Pc.

The present invention is achieved focusing on such a problem, and anobject thereof is to provide a capacity control valve having highresponsiveness even upon a radical output change.

Solution to Problem

In order to solve the foregoing problem, a capacity control valveaccording to the present invention is a capacity control valveincluding: a valve housing provided with a suction fluid supply chamberto which a suction fluid of suction pressure is supplied, and a controlfluid supply chamber to which a control fluid of control pressure issupplied; a CS valve formed by a CS valve element driven in an axialdirection by a solenoid, and a CS valve seat provided in a communicationpassage between the control fluid supply chamber and the suction fluidsupply chamber, the CS valve being connectable to and separable from theCS valve seat; and a pressure drive portion arranged in the controlfluid supply chamber in a sealed manner and biasing the CS valve elementin an opposite direction to a driving direction of the solenoid, whereinthe control fluid is introduced on a first side of the pressure driveportion, and the suction fluid is introduced on a second side of thepressure drive portion, the first side and the second side being opposedto each other through the pressure drive portion in the axial direction.According to the forgoing feature of the present invention, the controlfluid is applied on the outside which is the first side of the pressuredrive portion, and the suction pressure is applied on the inside whichis the second side. Thus, it is possible to adjust an opening degree ofthe CS valve by a pressure difference between the suction pressure ofthe suction fluid and the control pressure of the control fluid, andhence make adjustment to target control pressure Pc with high precision.Therefore, responsiveness is high even to a radical output change, andit is possible to promptly control a variable displacement compressor tothe target control pressure Pc.

It may be preferable that an effective pressure receiving area of thepressure drive portion is larger than an area of a valve opening of theCS valve seat. According to this preferable configuration, at the timeof driving the solenoid, the control pressure is applied in thedirection in which the pressure drive portion is against the drivingdirection thereof, for example, in the direction of contracting in acompression type pressure drive portion. Thus, it is possible toreliably ease the suction pressure by the control pressure.

It may be preferable that the capacity control valve further includes aretaining member that retains the pressure drive portion, wherein theretaining member is provided with a supply port communicating with aninside of the pressure drive portion, the supply port being directed inthe axial direction. According to this preferable configuration, thesuction fluid is supplied from the supply port in the axial direction.Thus, the suction pressure of the suction fluid is easily transmitted tothe pressure drive portion.

It may be preferable that the capacity control valve further includes areturn spring that is provided separately from the pressure driveportion and biases the CS valve element in the opposite direction to thedriving direction of the solenoid, wherein the CS valve element and thepressure drive portion are out of contact upon a non-driving state ofthe solenoid. According to this preferable configuration, the valveelement and the pressure drive portion are out of contact upon anon-driving state of the solenoid. Thus, it is possible to smoothlyoperate the valve element at the time of driving the solenoid, andensure a vibration suspending property by the return spring at the timeof a non-contact state of the valve element and the pressure driveportion.

It may be preferable that the pressure drive portion includes a springthat biases the CS valve element in the opposite direction to thedriving direction of the solenoid, and the spring may have a springconstant higher than a spring constant of the return spring. Accordingto this preferable configuration, in a state where the CS valve elementis in contact with the pressure drive portion, bias force of the springhaving a higher spring constant than the return spring is dominantlyapplied to the CS valve element. Thus, it is possible to increasecontrol width of an electric current applied to the solenoid to finelymake adjustment of the opening degree of the CS valve.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a sectional view showing a structure of a capacity controlvalve according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a state where a CS valve is opened ina non-energized state of the capacity control valve according to thefirst embodiment of the present invention.

FIG. 3 is a sectional view showing a state where a drive rod is incontact with a pressure sensitive body in an energized state of thecapacity control valve according to the first embodiment of the presentinvention.

FIG. 4 is an illustrative view of bias force applied to the drive rod atthe time of opening and closing the CS valve in the first embodiment ofthe present invention.

FIG. 5 is an illustrative view showing a case where a pressuredifference between suction pressure and control pressure is large in thecapacity control valve according to the first embodiment of the presentinvention.

FIG. 6 is an illustrative view showing a case where the pressuredifference between the suction pressure and the control pressure issmall in the capacity control valve according to the first embodiment ofthe present invention.

FIG. 7A is an illustrative view showing a case where a pressuredifference between suction pressure and control pressure is large in acapacity control valve according to a second embodiment of the presentinvention; and FIG. 7B is an illustrative view showing a case where thepressure difference between the suction pressure and the controlpressure is small in the same capacity control valve.

DESCRIPTION OF EMBODIMENTS

Modes for carrying out a capacity control valve according to the presentinvention will be described below based on embodiments.

First Embodiment

A capacity control valve according to a first embodiment of the presentinvention will be described with reference to FIGS. 1 to 6. Hereinafter,description will be given with the left and right sides seen from thefront side of FIG. 1 being the left and right sides of the capacitycontrol valve.

A capacity control valve V of the present invention is assembled into avariable displacement compressor (not shown) used for an airconditioning system of an automobile, etc. By variably controllingpressure of a working fluid (hereinafter, simply referred to as the“fluid”) serving as a coolant, a discharge amount of the variabledisplacement compressor is controlled and the air conditioning system isadjusted to have a target cooling ability.

First, the variable displacement compressor will be described. Thevariable displacement compressor has a casing including a dischargechamber, a suction chamber, a control chamber, and plural cylinders. Acommunication passage providing direct communication between thedischarge chamber and the control chamber is provided in the variabledisplacement compressor. A fixed orifice 9 is provided in thiscommunication passage (see FIG. 1).

The variable displacement compressor also includes a rotating shaft tobe driven and rotated by an engine (not shown) installed outside thecasing, a swash plate coupled to the rotating shaft in an eccentricstate by a hinge mechanism in the control chamber, and plural pistonscoupled to the swash plate and fitted reciprocatably in the respectivecylinders. With using the capacity control valve V to be driven to openand close by electromagnetic force, a tilt angle of the swash plate iscontinuously changed by appropriately controlling pressure in thecontrol chamber while utilizing suction pressure Ps of the suctionchamber that suctions the fluid, discharge pressure Pd of the dischargechamber that discharges the fluid pressurized by the pistons, andcontrol pressure Pc of the control chamber that houses the swash plate.Thereby, a stroke amount of the pistons is changed to control adischarge amount of the fluid.

As shown in FIG. 1, the capacity control valve V assembled into thevariable displacement compressor adjusts an electric current energizedin a coil 86 forming a solenoid 80 and performs open/close control of aCS valve 50 in the capacity control valve V, that is, the valve thatopens and closes communication between a control port and a suctionport, and by operating a pressure sensitive body 61 serving as apressure drive portion and controlling the fluid flowing out to thesuction chamber from the control chamber, the control pressure Pc in thecontrol chamber is variably controlled. A discharge fluid of thedischarge pressure Pd of the discharge chamber is always supplied to thecontrol chamber via the fixed orifice 9, and the control pressure Pc inthe control chamber can be increased by closing the CS valve 50 in thecapacity control valve V.

Next, a structure of the capacity control valve V will be described. Asshown in FIG. 1, the capacity control valve V is mainly formed by avalve housing 10 made of a metal material or a resin material, a CSvalve element 51 arranged reciprocatably in the axial direction, thepressure sensitive body 61 arranged in a control fluid supply chamber 17which is provided in the valve housing 10, the pressure sensitive bodythat applies bias force to the CS valve element 51 in the axialdirection, and the solenoid 80 connected to the valve housing 10, thesolenoid that applies drive force to the CS valve element 51.

In the valve housing 10, a Ps port 13 serving as a suction port whichcommunicates with the suction chamber of the variable displacementcompressor, a suction fluid supply chamber 16 to which a suction fluidis supplied from the Ps port 13, a Pc port 15 serving as a control portwhich communicates with the control chamber of the variable displacementcompressor, the control fluid supply chamber 17 to which a control fluidis supplied from the Pc port 15, and a communication passage 14providing communication between the suction fluid supply chamber 16 andthe control fluid supply chamber 17 are formed.

A hole portion 10 c passing through in the axial direction is formed inan axially left end portion of the valve housing 10, and the holeportion 10 c is closed by a lid member 11. Between this valve housing 10and the lid member 11, the pressure sensitive body 61 is nipped andretained. That is, the lid member 11 functions as a retaining memberthat retains the pressure sensitive body 61. A supply port 11 a passingthrough in the axial direction is formed in the lid member 11, and thesupply port 11 a communicates with the suction chamber. The pressuresensitive body 61 may be fixed to the lid member 11 or the valve housing10 by bonding or welding.

A guide hole 10 b passing through in the axial direction is formed in anaxially right end portion of the valve housing 10. An axially left endportion of a drive rod 83 to be described later is inserted through theguide hole, and the guide hole functions as a guide when the drive rod83 is driven in the axial direction.

The solenoid 80 is mainly formed by a casing 81 having an openingportion 81 a which is open on the axially left side, a substantiallycylindrical center post 82 inserted into the opening portion 81 a of thecasing 81 from the axially left side and fixed on the radially innerside of the casing 81, the drive rod 83 inserted through an insertionhole 82 c of the center post 82 reciprocatably in the axial direction, amovable iron core 84 to which an axially right end portion 83 c of thedrive rod 83 is inserted and fixed, a coil spring 85 provided betweenthe center post 82 and the movable iron core 84, the coil spring servingas a return spring that biases the movable iron core 84 to the axiallyright side which is the valve opening direction of the CS valve 50, andthe excitation coil 86 wound on the outside of the center post 82 via abobbin.

The drive rod 83 is formed in a stepped columnar shape, and also servesas the CS valve element 51. From the axially left side, an axially leftend portion 83 a serving as an axial portion having a small diameter, alarge diameter portion 83 b having a larger diameter than the axiallyleft end portion 83 a, and the axially right end portion 83 c having asmaller diameter than the large diameter portion 83 b are formed. Anaxially left end outer diameter portion 53 of the large diameter portion83 b is connectable to and separable from a CS valve seat 10 a. That is,the CS valve 50 is formed by the axially left end outer diameter portion53 of the CS valve element 51 and the CS valve seat 10 a, and byconnecting and separating the CS valve element 51 to and from the CSvalve seat 10 a, the CS valve 50 is opened and closed. In a state wherethe solenoid 80 is turned off, the CS valve element 51 is biased in thevalve opening direction of the CS valve 50 by the coil spring 85.

The pressure sensitive body 61 is mainly formed by a film body 62 madeof a flexible metal material or a flexible resin material, the film bodybeing extendable and contractible in the axial direction, and a spring63 arranged inside the film body 62. The film body 62 includes apressure receiving portion 62 a which is orthogonal in the axialdirection, a side wall portion 62 b extending on the axially left sidefrom a peripheral edge of the pressure receiving portion 62 a, and aflange portion 62 c extending in the radially outward direction from anaxially left end of the side wall portion 62 b, and has a hat-shapedsection. An O ring is arranged between the flange portion 62 c and thelid member 11 and attached to the valve housing 10 in a substantiallysealed manner. The supply port 11 a of the lid member 11 communicateswith the inside 61 s serving as a space on the other side of this filmbody 62, and the suction fluid can flow into the inside from the supplyport 11 a. That is, the suction fluid exists on the inside of the filmbody 62, i.e., the inside 61 s of the pressure sensitive body 61 and thecontrol fluid in the control fluid supply chamber 17 exists on theoutside serving as a space on one side of the film body 62. The spring63 is a spring having a higher spring constant K63 than a springconstant K85 of the coil spring 85 (K63>K85), and biases to press thepressure receiving portion 62 a of the film body 62 to the axially rightside.

As shown in FIG. 2, an effective pressure receiving area A of thepressure sensitive body 61 is formed to be larger than a sectional areaB of the communication passage 14 serving as a valve opening of the CSvalve seat 10 a (A>B).

Next, actions of the capacity control valve V, mainly actions of openingand closing the CS valve 50 will be described.

First, a non-energized state of the capacity control valve V will bedescribed. As shown in FIGS. 1 and 2, in the capacity control valve V,in a non-energized state, by pressing the movable iron core 84 to theaxially right side by bias force of the coil spring 85, the CS valveelement 51 is separated from the CS valve seat 10 a, and the CS valve 50is opened.

At this time, to the CS valve element 51, the bias force F_(sp1) of thecoil spring 85 and force F_(P1) by pressure of the fluid to an axiallyleft end surface of the CS valve element 51 are applied to the axiallyright side, and force F_(P2) by pressure of the fluid to an axiallyright end surface of the CS valve element 51 is applied to the axiallyleft side. That is, given that the right side is the positive side,force F_(rod)=F_(sp1)+F_(P1)−F_(P2) is applied to the CS valve element51. At the time of opening the CS valve 50, the force F_(P1) by thepressure of the fluid to the axially left end surface of the CS valveelement 51 is force by pressure of the fluid in the suction fluid supplychamber 16, and the force F_(P2) by the pressure of the fluid to theaxially right end surface of the CS valve element 51 is force bypressure of the fluid running round from the suction fluid supplychamber 16 to the back surface side of the drive rod 83 via a gapbetween an inner peripheral surface of the guide hole 10 b of the valvehousing 10 and an outer peripheral surface of the CS valve element 51.The pressure in the suction fluid supply chamber 16 is based on thecontrol pressure Pc and the suction pressure Ps which are lower than thedischarge pressure Pd. Thus, an influence of the forces F_(P1), F_(P2)by the pressure to the CS valve element 51 is small.

Next, an energized state of the capacity control valve V will bedescribed. As shown in FIGS. 1 and 3, in the capacity control valve V,in an energized state, that is, at the time of normal control, at thetime of so-called duty control, when electromagnetic force F_(sol)generated by applying an electric current to the solenoid 80 exceeds theforce F_(rod) (i.e., F_(sol)>F_(rod)), by pulling the movable iron core84 to the center post 82 side, that is, to the axially left side, andmoving the CS valve element 51 fixed to the movable iron core 84 to theaxially left side together, the axially left end portion 83 a is broughtinto contact with the pressure sensitive body 61.

Before the axially left end portion 83 a is brought into contact withthe pressure sensitive body 61, to the CS valve element 51, theelectromagnetic force F_(sol) is applied on the axially left side, andthe force F_(rod) is applied on the axially right side. That is, giventhat the right side is the positive side, force F_(rod)−F_(sol) isapplied to the CS valve element 51. After the axially left end portion83 a is brought into contact with the pressure sensitive body 61, forceF_(bel) is further added to the axially right side from the pressuresensitive body 61. The force F_(bel) applied from the pressure sensitivebody 61 is force obtained by subtracting the force F_(Pc-Ps) based on apressure difference between the control pressure Pc and the suctionpressure Ps from bias force F_(sp2) of the spring 63, and given that theright side is the positive side, F_(bel)=F_(sp2)−F_(Pc-Ps) is applied.At the time of considering bias force of the film body 62 itself, thebias force of the film body 62 itself may be added to the bias force ofthe spring 63 itself.

With reference to FIG. 4, to the CS valve element 51, in a non-energizedstate of the capacity control valve V, the bias force F_(sp1) of thecoil spring 85 is applied to the axially right side, and the drive rod83 is pressed to the right side. Thus, a vibration suspending propertyof the drive rod 83 is ensured. In an energized state of the capacitycontrol valve V, before the axially left end portion 83 a of the driverod 83 is brought into contact with the pressure sensitive body 61, itis possible to smoothly operate the drive rod 83. After the axially leftend portion 83 a of the drive rod 83 is brought into contact with thepressure sensitive body 61, the bias force F_(sp2) of the spring 63 ofthe pressure sensitive body 61 having a higher spring constant than thecoil spring 85 is dominantly applied to the drive rod 83. Thus, controlwidth of an electric current applied to the solenoid 80 is increased andit is possible to finely make adjustment of an opening degree of the CSvalve 50.

Specifically, in a state where the axially left end portion 83 a of thedrive rod 83 and the pressure sensitive body 61 are in contact with eachother, a high spring load is applied. Thus, a stroke of the drive rod 83per unit applied electric current is shortened, and the opening degreeof the CS valve 50 is more easily finely adjusted.

Next, a change in the control pressure and the suction pressure in astate where a predetermined electric current is applied to the solenoid80, that is, in a state where predetermined electromagnetic forceF_(sol) 1 is generated in the solenoid 80 will be described.Hereinafter, a mode when an operation of increasing an output of the airconditioning system is performed, an output of an expansion valve of theair conditioning system is increased, and a flow rate of the suctionfluid supplied to the suction chamber of the variable displacementcompressor and the suction pressure Ps are increased will beillustrated.

As shown in FIG. 5, in a state where the predetermined electromagneticforce F_(sol) 1 is generated in the solenoid 80 and the CS valve 50 isclosed, and in a case where an increase in the suction pressure Ps issmall, the pressure difference between the suction pressure Ps in thepressure sensitive body 61 and the control pressure Pc in the controlfluid supply chamber 17 is large. Therefore, the pressure sensitive body61 is more easily contracted by the control pressure Pc in the controlfluid supply chamber 17, the CS valve element 51 is seated on the CSvalve seat 10 a of the valve housing 10, and a closed state of the CSvalve 50 is maintained. At the time of closing the CS valve 50, theforce F_(P1) by the pressure of the fluid to the axially left endsurface of the CS valve element 51 is force by the control pressure Pcof the control fluid of the Pc port 15.

Meanwhile, as shown in FIG. 6, in a state where the predeterminedelectromagnetic force F_(sol) 1 is generated in the solenoid 80 and theCS valve 50 is closed, and in a case where the increase in the suctionpressure Ps is large, the pressure difference between the suctionpressure Ps in the pressure sensitive body 61 and the control pressurePc in the control fluid supply chamber 17 is small. Therefore, thepressure sensitive body 61 is less easily contracted by the controlpressure Pc in the control fluid supply chamber 17 than the state ofFIG. 5, the CS valve element 51 is separated from the CS valve seat 10 aof the valve housing 10, and the CS valve 50 is slightly opened.

In such a way, the suction pressure Ps is applied on the inside of thepressure sensitive body 61, and the control pressure Pc is applied onthe outside of the pressure sensitive body 61. Thus, even when theoutput of the expansion valve of the air conditioning system isincreased and the suction pressure Ps of the suction fluid supplied tothe suction chamber of the variable displacement compressor is radicallyincreased, the pressure sensitive body 61 can utilize the pressuredifference between the control pressure Pc of the control fluid and thesuction pressure Ps of the suction fluid, and adjust the opening degreeof the CS valve 50. Therefore, responsiveness is high even to a radicaloutput change, and it is possible to promptly control the variabledisplacement compressor to target control pressure Pc.

The effective pressure receiving area A of the pressure sensitive body61 is formed to be larger than the sectional area B of the communicationpassage 14. Thus, at the time of driving the solenoid 80, the controlpressure Pc is applied in the direction in which the pressure sensitivebody 61 is contracted, and it is possible to reliably ease the suctionpressure Ps by the control pressure Pc.

The supply port 11 a passing through in the axial direction is formed inthe lid member 11, and the suction fluid is directed in the axialdirection and supplied from the supply port 11 a into the pressuresensitive body 61. Thus, it is possible to immediately transmit thesuction pressure Ps of the suction fluid to the pressure receivingportion 62 a of the pressure sensitive body 61.

The CS valve seat 10 a and the guide hole 10 b are integrally formed inthe valve housing 10. Thus, it is possible to enhance precision of anaction of the CS valve element 51.

Second Embodiment

A capacity control valve according to a second embodiment of the presentinvention will be described with reference to FIG. 7. Duplicateddescription for the same configurations as the first embodiment isomitted.

As shown in FIG. 7, in the present embodiment, a CS valve 150 is formedby a projecting portion 153 projecting in the radially outward directionfrom the vicinity of an axially left end portion 831 a of a drive rod831, and a CS valve seat 110 a formed in an inner diameter portion in anopening portion on the axially left side of a communication passage 14of a valve housing 10. That is, the drive rod 831 also serves as a CSvalve element 151, and the CS valve 150 is formed by the projectingportion 153 of the CS valve element 151 and the CS valve seat 110 a. Theprojecting portion 153 of the CS valve element 151 is arranged in acontrol fluid supply chamber 17. By connecting and separating an axiallyright side surface of the projecting portion 153 to and from the CSvalve seat 110 a, the CS valve 150 is opened and closed. The drive rod831 is moved to the axially right side by driving a solenoid. Theaxially left end portion 831 a of the drive rod 831 is connected to apressure sensitive body 611.

Although not shown, a coil spring serving as a return spring of thepresent embodiment is arranged to bias the drive rod 831 to the axiallyleft side which is the valve opening direction of the CS valve 150. Thatis, although the structures are different, both the capacity controlvalves V of the first and second embodiments are normally-opened valves.Therefore, in a non-energized state of the capacity control valve V, bypressing a movable iron core 84 to the axially left side by bias forceof the coil spring, the projecting portion 153 of the CS valve element151 is separated from the CS valve seat 110 a, and the CS valve 150 isopened. At this time, regarding the drive rod 831, in a case where apressure difference between suction pressure Ps of the pressuresensitive body 611 and control pressure Pc in the control fluid supplychamber 17 is large, bias force of the pressure sensitive body 611 ishardly applied to the drive rod 831.

As shown in FIG. 7A, in an energized state of the capacity control valveV, in a case where the pressure difference between the suction pressurePs of the pressure sensitive body 611 and the control pressure Pc in thecontrol fluid supply chamber 17 is large, the pressure sensitive body611 is contracted. Thus, the bias force of the pressure sensitive body611 is applied in the direction in which the drive rod 831 is pulled tothe axially left side, the projecting portion 153 of the CS valveelement 151 is separated from the CS valve seat 110 a, and the CS valve150 is slightly opened.

Meanwhile, as shown in FIG. 7B, in an energized state of the capacitycontrol valve V, in a case where the pressure difference between thesuction pressure Ps of the pressure sensitive body 611 and the controlpressure Pc in the control fluid supply chamber 17 is small, thepressure sensitive body 611 is extended. Thus, the bias force of thepressure sensitive body 611 is applied in the direction in which thedrive rod 831 is pushed out to the axially right side, the projectingportion 153 of the CS valve element 151 is seated on the CS valve seat110 a, and the CS valve 150 is closed.

By forming in such a manner, the capacity control valve can be effectivefor a variable displacement compressor in which the higher the controlpressure Pc in a control chamber is, the more a stroke amount of pistonsis increased, and the lower the control pressure Pc in the controlchamber is, the more the stroke amount of the pistons is decreased.

The embodiments of the present invention are described above with thedrawings. However, specific configurations are not limited to theseembodiments but the present invention includes changes and additionswithin the range not departing from the scope of the present invention.

For example, the above embodiments describe the mode that the CS valveelement also serves as the drive rod arranged to pass through the coil86 of the solenoid 80. However, the present invention is not limited tothis but the CS valve element may be formed separately from the driverod and formed reciprocatably in the axial direction together with thedrive rod.

The above embodiments describe that the CS valve seat and the guide holeare integrally formed on the inner peripheral surface of the valvehousing. However, the present invention is not limited to this but avalve housing having a CS valve seat and a valve housing having a guidehole may be separately provided.

A guide portion is not limited to be formed in the valve housing but maybe formed in part of the insertion hole 82 c of the center post 82, forexample.

REFERENCE SIGNS LIST

-   -   10 Valve housing    -   10 a CS valve seat    -   11 Lid member    -   11 a Supply port    -   13 Ps port    -   14 Communication passage (valve opening)    -   15 Pc port    -   16 Suction fluid supply chamber    -   17 Control fluid supply chamber    -   50 CS valve    -   51 CS valve element    -   61 Pressure sensitive body (pressure drive portion)    -   61 s Inside of pressure drive portion    -   63 Spring    -   80 Solenoid    -   83 Drive rod    -   85 Coil spring (return spring)    -   110 a CS valve seat    -   150 CS valve    -   151 CS valve element    -   611 Pressure sensitive body    -   831 Drive rod    -   Pc Control pressure    -   Pd Discharge pressure    -   Ps Suction pressure    -   V Capacity control valve

1: A capacity control valve comprising: a valve housing provided with asuction fluid supply chamber to which a suction fluid of suctionpressure is supplied, and a control fluid supply chamber to which acontrol fluid of control pressure is supplied; a CS valve formed by a CSvalve element driven in an axial direction by a solenoid, and a CS valveseat provided in a communication passage between the control fluidsupply chamber and the suction fluid supply chamber, the CS valve beingconnectable to and separable from the CS valve seat; and a pressuredrive portion arranged in the control fluid supply chamber in a sealedmanner and biasing the CS valve element in an opposite direction to adriving direction of the solenoid, wherein the control fluid isintroduced on a first side of the pressure drive portion, and thesuction fluid is introduced on a second side of the pressure driveportion, the first side and the second side being opposed to each otherthrough the pressure drive portion in the axial direction. 2: Thecapacity control valve according to claim 1, wherein an effectivepressure receiving area of the pressure drive portion is larger than anarea of a valve opening of the CS valve seat. 3: The capacity controlvalve according to claim 1, further comprising a retaining member thatretains the pressure drive portion, wherein the retaining member isprovided with a supply port communicating with an inside of the pressuredrive portion, the supply port being directed in the axial direction. 4:The capacity control valve according to claim 1, further comprising areturn spring that is provided separately from the pressure driveportion and biases the CS valve element in the opposite direction to thedriving direction of the solenoid, wherein the CS valve element and thepressure drive portion are out of contact upon a non-driving state ofthe solenoid. 5: The capacity control valve according to claim 4,wherein the pressure drive portion includes a spring that biases the CSvalve element in the opposite direction to the driving direction of thesolenoid, and the spring has a spring constant higher than a springconstant of the return spring. 6: The capacity control valve accordingto claim 2, further comprising a retaining member that retains thepressure drive portion, wherein the retaining member is provided with asupply port communicating with an inside of the pressure drive portion,the supply port being directed in the axial direction. 7: The capacitycontrol valve according to claim 2, further comprising a return springthat is provided separately from the pressure drive portion and biasesthe CS valve element in the opposite direction to the driving directionof the solenoid, wherein the CS valve element and the pressure driveportion are out of contact upon a non-driving state of the solenoid. 8:The capacity control valve according to claim 7, wherein the pressuredrive portion includes a spring that biases the CS valve element in theopposite direction to the driving direction of the solenoid, and thespring has a spring constant higher than a spring constant of the returnspring. 9: The capacity control valve according to claim 3, furthercomprising a return spring that is provided separately from the pressuredrive portion and biases the CS valve element in the opposite directionto the driving direction of the solenoid, wherein the CS valve elementand the pressure drive portion are out of contact upon a non-drivingstate of the solenoid. 10: The capacity control valve according to claim9, wherein the pressure drive portion includes a spring that biases theCS valve element in the opposite direction to the driving direction ofthe solenoid, and the spring has a spring constant higher than a springconstant of the return spring.